This invention relates to a system for rapidly cooling comestibles which are in a liquid or a semisolid state and which are stored in tightly spaced vertically stacked banks of shallow trays or receptacles.
If certain foods are allowed to remain warm they will offer a favorable environment for harmful bacteria that can proliferate rapidly. These organisms may elaborate toxins as they multiply and they will survive while the food is in storage. Subsequent consumption of such contaminated food may introduce dangerous toxins and viable infective organisms into the alimentary tract and cause illness or death. Cooking the food prior to consumption will not avoid risk of harm. While most of the bacteria will not survive the cooking process, some bacterial toxins are not inactivated by heat.
Since bacteria cannot grow at low temperatures, it is important to rapidly chill potentially hazardous foods prior to refrigerated storage, thus minimizing the risk of human illness. Many health codes require that potentially hazardous foods be immediately chilled in shallow containers so that chilling is complete and no isolated warm regions remain in the food. In facilities which manufacture food products or serve large numbers of people it is necessary to store food in many shallow containers under circumstances where storage is at a premium. The food can most efficiently be stored in tiers of vertically aligned shallow trays or receptacles with a narrow space separating each tier. Commercially available containers do not provide this desired geometry in that they are overly deep and capacious, and therefore are not adapted for storing potentially hazardous foods in accordance with modern health codes.
A number of devices for chilling beverages and the like are known. U.S. Pat. No. 1,923,522 to Whitehouse discloses a biconcave box of celluloid or other flexible plastic material which can be filled with water and frozen. The frozen box can then be placed in a beverage where it will either lie submerged or will float on the surface and absorb heat energy from the beverage. U.S. Pat. No. 4,325,230 to Driscoll et al discloses a rigid plastic cube filled with water which can be frozen and placed in a liquid to be cooled. U.S. Pat. No. 4,761,314 to Marshall shows a plastic shell filled with a medium which freezes at about the freezing temperature of water and is to be placed in a beverage or other liquid to be cooled. This shell has a complex shape, being provided with numerous projections and invaginations to increase the surface area in contact with the liquid to be chilled. The device can be weighted to lie at the bottom of the liquid or have neutral buoyancy. These prior art devices all cool the liquid passively and must eventually be extracted by some instrumentality that comes in contact with the chilled liquid. In the case of food, such a procedure risks introducing bacterial contamination and is therefore extremely undesirable and potentially dangerous. Furthermore these devices lie motionless in the material being cooled. Their cooling effect is greatest immediately adjacent the device and dissipates rapidly with the distance from the device. Bacteria can thus grow in regions which are remote from the device and shielded from the cooling influence thereof.
U.S. Pat. No. 1,758,008 to Mock shows a refrigerating device in which a container enclosing a refrigerant has a handle to allow a user to submerge the container in a liquid to be cooled and stir the same. The unit has a relatively enlarged refrigerating container and a narrow elongated handle. This device is suitable for refrigerating a material in a relatively large receptacle, but is too bulky for convenient insertion into shallow containers which are arranged in closely spaced vertical banks. Furthermore this device requires the refrigerant to communicate with the ambient air through a hole in the handle. This device is suitable for vertical insertion into a container, but its use in food storage in other than a vertical position would be unsafe because refrigerant could flow out of the device through the handle and could contaminate the food.